Siemens LMV5 Quick Start Manual page 37

Load Controller
The LMV51.140 and all LMV52 are equipped with a Load Controller (LC). The LC is very
flexible and can read multiple sensors simultaneously. Typically, either a temperature sensor or
pressure sensor is connected for burner modulation. Both a pressure and a temperature sensor
can be used in conjunction for certain applications such as Cold Start Thermal Shock
Protection.
The LC also has six different operational modes that can be changed by opening or closing a
set of dry contacts. These six different modes of operation are outlined in Section 4-1. By using
a dry contact between terminals X62.1 and X62.2, the mode and / or setpoint of the internal load
controller can be changed by closing or opening the contact.
If the LC is in Mode 2, which is Internal Load Controller (Int LC), setpoint W1 will be used if the
dry contact is open and setpoint W2 will be used if the dry contact is closed.
If the LC is in mode 1A, 1B, 3, 4, 5, or 6, and the dry contact is closed, the LMV5 will revert back
to mode 2 and will use setpoint W1.
This feature is commonly used when switching the LMV5 from Mode 5 (direct modulation via a
4-20mA source wired into terminals X62.3 and X62.4) back to Mode 2 for local sensing and
modulation of the burner.
Note: Please see Section 4-1 for more information on LC modes.
The LC also provides power for 4-20mA loop powered sensors or 0 -10 VDC externally powered
sensors. The wiring of these sensors is covered in Section 3-3. Description of the LC is
provided in Section 4, page 15.
Floating / Bumping and Multi-stage Oil
Terminals X5-03.02 and X5-03.03 can be used for floating / bumping or multistage oil. This can
be done on all models of LMV5 and is typically done on LMV51.040 models.
Through the use of floating / bumping, the LMV5 can be driven to high fire by placing line
voltage on terminal X5-03.02 and to low fire by removing line voltage from X5-03.02 and placing
line voltage on X5-03.03. By alternating voltage on these terminals the firing rate of the LMV5
equipped burner can be increased or decreased. The floating / bumping type of modulation is
typically what is used if the LMV5 is modulated with a RWF40.
A relay can be placed in the line connected to X5-03.02 if a low fire hold is desired.
If externally controlled multistage oil is selected terminal X5-03.02 can be energized with line
voltage to put the burner in Stage 2, and terminal X5-03.03 can be energized with line voltage to
put the burner in Stage 3. De-energizing these terminals takes the burner out of stage 2 or
stage 3.
In all cases (unless terminal X5-03.01 is deactivated) energizing terminal X5-03.01 turns the
burner on, and de-energizing terminal X5-03.01 turns the burner off.
LMV5 QSG Rev 4 Sec 3 Pg 5 www.scccombustion.com